1. Field of the Invention
This invention is related to loading coil assemblies. In particular, the invention is directed to such assemblies for use in communication transmission lines.
2. Description of the Prior Art
The loading coil has been used in the telephone communication system for over 75 years and is placed approximately every 6,000 feet in a transmission line to provide a lumped inductance to cancel the distributed capacitance in a wire pair. With hundreds of wire pairs in a transmission cable, it is necessary to store the loading coils in protective containers which can be mounted aerially, on a pole or in a manhole. A variety of containers have been designed to accommodate differing numbers of load coils. Historically, coils were mounted on wooden dowels and placed in a cylindrical container with the coil leads extending therefrom. A plurality of such containers were positioned about a transmission cable and the leads soldered to the lines to be loaded as shown in U.S. Pat. No. 2,548,199 which issued to Crane et al. on Apr. 10, 1951 and is assigned to the instant assignee.
A further improvement of such an arrangement is shown in U.S. Pat. No. 3,865,980 which issued to Moser et al. on Feb. 11, 1975 and discloses a compartmented module having a substantially semi-circular cross section. A load coil is placed in each compartment and the leads from the coils soldered to first ends of terminal elements. The terminal elements are mounted on the sides of the module where the line to be loaded is connected to a second end of the terminal element.
In recent years, cables have been fabricated with the cable wires terminated in connectors at the manufacturing location, for purposes of a quick solderless splice connection to another cable. Accordingly, it is most desirable to arrange load coil modules with mating connectors so that the coils may be inserted or removed from the transmission line without the need of having to unsolder and/or resolder a multitude of leads. One such load coil module is described in U.S. patent application No. 864,303 filed on Dec. 27, 1977 in the name of R. J. Reinebach and which is assigned to the instant assignee. That coil module has a substantially oval cross section with two rows of load coils encapsulated therein in a potting compound. Leads from the coils are soldered to smaller gauge wire which extend from the module in a pig-tail fashion. The pig-tail leads are terminated in at least one pair of male and female connectors for connection to a connectorized cable.
Such an arrangement has been found to be most effective for connecting load coils into transmission lines. However, the pig-tail arrangement is space inefficient and the soldering of the load coil wires to the smaller gauge connecting wires is time consuming and expensive.